Pneumatic tool.



PATENTBD AyB. 28, 1908.

H. M. DUNLAP. PNEUMATICI TOOL. APPLIUATION FILED 1211.18. 1904.

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Witlgsses:

TENT UFFIQ.

HARLEY M. DNLAP, OF BATTLE CREEK, MICHIGAN.

PNEUMATIC Toon.

Specicatibn-of Letters Patent.

Patented April 28, 1908.

Application filed April 18, 1904. `Serial No. 203,724.

Y To all 'whom/it concern:

Beit known that l, HARLEY M. DUNLAP,`a citizen of the United States, residing at the city of Battle Creek, in the county of Calhoun, State of Michigan, have invented certain new and useful mprovements in Pneumatic Tools, of which the following'is a specification.

This invention relates to improvements in pneumatic tools.

My improved pneumatic tool is particularly adapted for use as a massaging device or hammer for giving massage treatments, although it is adapted for other uses such as pneumatic hammers and the like are generally applied to.

The objects of this invention are-First, to provide an improved pneumatic tool or hammer which is simple in'v structure and plunger B. The up economical to produce-and convenient economical and durable in use. Second, to produce an improved pneumatic tool adapted for use as a massage device or hammer for Giving massage treatments adapted to produce a very rapidvibratvory movement and one which is under the control of the operator.

Further objects and objects relatin to structural details will definitely appear rom the detailed description to follow.

I accomplish the objects of my invention by the devices and means described in. the following specification.

he invention is clearly defined and pointed out in the claims. 4

A structure-embodying thefeatures of my invention is clearly illustrated in the accompanying -drawing forming a part of this specification, in which,

Figure l is a central longitudinal sectional view through a structure embodying the feat res of my invention. Fig. 2 is a detail longitudinal sectional view of structure showing a movable tool holder or socket.

Referring to the drawing, acylinder A having heads A A is rovided. These heads are preferably screwt eaded vonto the cylinderso that the parts are readily assembled. The head. Ay is rovided with .a tool holder or socket a ma e integral therewith. 'Within the cylinder A isr a piston or er .or outer portion nf thepiston B is provi ed with a central longithe outer end of the-piston.

tudinal chamber-like l'passage g ope at The piston Bis exhaust port and the annular passage are so which the coiled spring a rests.

cated in dotted lines.

a modified also providedwith an annular groove-like as- This groove is connected to the ongitudinal passage or chamber g by radial passages g/. The groove b is adapted to register with theair inlet ,port d of the vcylinder when the lunver is in its initialor outer osition e P z and 1s out ofi' therefrom by the piston when it is in its inner position. The cylinder is rovided with an exhaust port c located be ow the inlet port d. This exhaust port is adapted to open into the annular passage or groove g when the piston is in its inner position. y

The lower portion of thepiston B is of reduced diameter to provide a shoulder against This spring serves to return the piston to its initialyposition. Arranged in a suitable seator socket in the head A of the cylinder, is afr'ebound s ring a which is adapted to receive4 the b ow of the piston and to aid inereturning it to its initial position. A vent port c is provided for the lower portion of the cylinder. This vent, allows the air in front of the iston to escape as the pistoniis forced inward y.

Airis supplied to the port d through the hollow stem D of the handle F. The handle F is provided with a nipple G adapted to receive'a suitable air supply pipe, as is indi- I control the deliveryl of air to the cylinder by an inwardly opening valve E which is provided with a stem E adapted to be actuated by the thumb of the user. The stem E is arranged through a chamber c. Supported within this chamber is a diaphragm e', dividing the chamber into two parts, the lower portion being connected to the air supply, s'o-that the valve is closed automatically, when it is released by the operator, by the air supply pressure. The valve stem E passes through and is connected t0 this diaphragm.

In operation, air is Aad "tted through the valve E, the same being opened inwardly by the pressure of the operator. y tering the annular passage b lthrough the inlet port d, passes thence throughthe passages b and b into the cylinder. This drives the `piston forward until the annular groove or passage B registers with lthe exhaust ports c, which allows the cylinder to exhaust. the annular passage it is of considerable width the fpiston continues to take air while the piston 1s moving forward until the intake port is covered. The intake port and the The air en- I desire'to remark t arranged that the intake is cut oif just as the exhaust port begins to open. By the impetus which the piston receives from the air and by the expansion of the air behind it, the piston is driven inward against the action of the return spring until it strikes the rebound spring a.l A s the cylinder is by this time exhausted, this throws the piston quickly back to the starting point. The result is that a vibratory movement is imparted -to the whole device. Thus arranged, the movement of the piston is very rapid.

at the rebound spring maybe omitted and stillvery satisfactory results -be secured. It is, however, of ad-4 vantage in that the return spring can then be of only suilicient vstrength to return the piston to its initial position. I further desire to remark that the returnspring may be omitted ifdesired, the rebound spring onlyl being used. In this case, it is necessary, however, that the piston be jarred or otherwise forced to its initial position at the outer end of the cylinder in starting. Thev action of the device is also less regular, its movement varying slightly according to the different positions in which the instrument is held. I preferably provide the return spring of just sucient strength to return the piston to its initial position against its own weight. The springs are very different from air confined by 'the piston because they are positive in their action, the parts need no iittlng to con-- iine the air and less friction is consequent and less force expended. l

In the modiiied structure shown in Fig. 2,

. a movable tool holder or socket Fis provided. This tool holder F is reciprocatingly secured in the head A by a thumb screw 1 which engages' a longitudinal lgroove therein. The inner end of the4 holder F is provided with a seat for the rebound spring a Thus arranged, the blows of the piston are delivered to the tool holder or socket.

In use, the rapidity of the vibration is controlled by the quantity of air admitted 'to the cylinder and the amount of pressure. The amount of air admitted can be easily `controlled by the o erator with the valve I have shown. y I am, owever, aware that there are numerous styles of valve which would prove satisfactory. 4

I have illustrated and described my i'mproved pneumatic tool in the form preferred y me on account of its structural simplicity and economy, and its convenience in'use. I

am, however, aware that it is capable of considerable variation in structural details without departlng from my invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a structure ,of the class described, the combination of a cylinder; a p'iston hav-l ing a longitudinal passage opening at its specified.

outer end and an annular passage connected tosaid longitudinal passage; an inlet port for said cylinder Aadapted to register with said annular passage when said piston is in its initial or outer position, and to be closed by said piston whenthe same is in 'its inner position; an exhaust port adapted to register with said -annular passage when said piston is in its inner position; a vent p'ort for the the combination of a cylinder; a piston hav-A ing a longitudinal passage opening at its outer end and an annular passage connected to said longxitudinal passage; an inlet port for said. cy nder adapted to register with said annular passage when said ,piston isin its initial or outer position, and to be closed by said piston when same is in its inner position; an exhaust portl adapted to register with said annular passage lwhen said'piston i-s in its inner position; a vent port for the inner end of said cylinder; a return s ring adapted to engage the lower end of sai piston; and a rebound spring adapted to receive the blows of said piston, for the purpose 3. In a structure of Ithe class de-scribed,

the combination of a cylinder; apiston having a longitudinal passagev opening at its outer end and an annular passage connected to-saidv longiltludinal passage; an inlet port g for said cy der adapted to register with said annular passage when said piston is in its initial orouter position, and to be closed by said piston when thesame is in its inner position; an exhaust port ada ted to register with said annular passage W en-.said iston is in its inner position; a vent port for t e inner end of said cylinder; a return s ring ladapted to en age the lower end of sai piston; a latera y projecting handle for fsaid cylinder, having a passage therethrough, connectedv to said mlet port; andan automatic valve adaptedto control said passage, ar- ;aiged in said' handle, for the purpose speciy 4; In a structure of the class described, the combination of a cylinder; a piston having a longitudinal passage opening at its outer` end, and an annular passage connected to said longitndinal'passage; an inlet port for said cyhnderadapted to'register with said annularp'assage when said iston is in lts initial or outer position, and)to be closed by said piston when' the same is in its inner position; an exhaust port adapted to register combination of a cylinder; a piston having alongitudinal passage opening at its outer end, and an annular passage connected to said longitudinal passage; an inlet port for said cylinder adapted to re'gister with saidannular passage when said iston is in its initial or outer position, an to be closed by said piston when the same is in its .inner position; an exhaust port adapted to register with said annular passage when said piston is in itsinner position; a return s ring adapted to engage the lower end of sai piston; a rebound spring adapted to receive the blows of said piston; and an automatic valve adapted to control said inlet port, for the purpose specified.

6. In a structure of the class described, the combination of a cylinder; a`piston having a longitudinal passage opening at its o ter end, and an annular passage connected o said longitudinal passage; an inlet port for said cylinder adapted to register withv said annular passage when saidpiston is in its initial or outer position, and to be closed by said piston when the same is in its inner position;

an exhaust port adapted to register with said annular passage when said piston is in its inner position; a return spring adapted to enage the lower end of said piston; and a reound spring adapted 'to receive the blowsy of said piston, for the urpose s eciiied.

7. Ina structure of t e class escribed, the combination of a cylinder; a piston having a longitudinal passage opening at its outer end and an annular passage connected to s aido -longitudinal passage; an inlet port for said cylinder adapted to register with said annu# lar passage when said piston is in its initial,

or outer position, and to be 'closed bysaid piston when the same is in its inner position; an exhaust port adapted to register Withsaid annular passage when said piston vis in its inner position; a movable tool holder or socket and a rebound spring for said piston, for the purpose speiciied.

In witness whereof, I' have hereunto set' my hand in the resence of two witnesses.

l l RLEY M.-DUNLAP Witnesses:

IRA A. BECK, 4 MILDRED PHILLIPS. 

